Electrically-operated telegraphic typewriting system



Sept. 16. 1954. 1,508,870

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OBIN BENNETT, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO PACIFIC COAST TYPE- WRITEB 00., OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

ELECTBICALLY-OPERATED TELEGRAPHIC TYPEWRITING SYSTEM.

Application filed May 27, 1.922. SerialNo. 564,013.

To all whom it may concern:

Be it known that I, ORIN BnNNm'r, a citizen of the United States, residing in the city and county of San'Francisco and State of California have invented certain new and useful Improvements in Electrically-Operated TelegraphicTypewriting Systems, of which the following is a specification.

The present invention relates to apparatus for the. transmission of written messages by electrically operated means.

The principal'object of the invention is to provide a printing telegraphic apparatus in which the possibility of error in the transmission of messages is reduced to a minimum. Other objects will become apparent from the following description of the invention.

Broadly speaking, the preferred embodiment of my invention comprises two or more identical machines, each havmg a key-board and a printing mechanism similar to those of a well-known form of typewriter, and

each being capable of either sending or receiving messages, at the will of the operator. The machines are connected together by a simple electric'circuit comprising two wires or their equivalent, and whatever devices, such as relays, etc. as may be rendered necessary by the distance between the machines and the length of the line. Any machine may be the sender, the others being the receivers. To avoid duplication in the following description, one machine only is deparatus,

pended claims,

scribed and illustrated, and in the description of the operation of the complete apthe simplest possible form, including only two machines, either of which may be the sender and the other the receiver, will be used by way of example, it being understood that any number of similar machines ma be included in the transmitting circuit. oreover, it is to be understood that changes, Within the scope of the ap may be made in the form and construction of the machine itself and its electrical connections and circuits, without departing from the spirit of the invention. as expressed in said claims.

The attainment of the principal object stated above, viz, the practical elimination of error, is brought about by providing a mutual inter-dependence between the sendngand receiving machines. Thus the printing mechanism of the receiving machine is sendmg machlne,

controlled by the key-board of the sending machine, but the printing mechanism of the instead of being controlled by its own" key-board, is controlled by the operation of the printing mechanism of the receiving machine. reason the printing mechanism of the receiving machine responds falsely to the keyboard of the sending machine, the printing mechanism of said sending machine if it responds at all, will print the same false letter that was printed by the receiving machine, thus warning the sendin operator at once that an error has occurre In most cases of trouble of any kind, either mechanical or electrical, the entire mechanism is so locked as to prevent further operation until the cause of the trouble has been ascertained and removed. I

In the preferred embodiment-of my invention, I make use of a writing machine of the well-known type in which the type characters are formed upon the outer surface of a cylindrical bod or wheel and are selected by the rotation 0' said wheel, such movement being caused by the partial operation of the keys. The printing of the selected letter is then. accomplished, by the further movenient of the same key, through suitable mechanism which causes the type wheel to move bodily down upon the paper, which is carried upon a platen roller mounted in the usual laterally movable carria e. The mechanical construction of sudh machines, which is well-known, forms no part of the present invention, and therefore has been omitted from the drawings, and the following description, except in so far as is necessary properly to illustrate and describe the novel mechanical and electrical features constituting the said invention.

Before proceeding with a more detailed "description of the invention, it will be necessary to outline the general principles of its preferred construction, as follows :the

imanual operation of any given key on the sending machine closes an electric circuit which sets in motion the selecting mechanism ofthe receiving machine. Said seiecting mechanism operates by. a series of automatic'and successive steps, and each step motion of the receiving machine causes a similar and corresponding action in the selecting mechanism of the sending machine. When this selecting operation, which re- Therefore, if for anytlie quires but a very short interval of time, is completed in both machines, other circuits are automatically closed, which cause the proper keys of both machines to be fully depressed, thereby printing the letter, through the ordinary mechanical action ofthe machines. The selecting mechanism of both machines then returns to the normal posi- .tion, and their platen carriages are advanced the space of one letter. The electric circuits are so arranged that the selecting operation, when once initiated, proceeds automatically in both machines to proper completion, and cannot be interfered with by the remature depressing or" another key. l oreover, the selecting mechanism of the sending machine is operated, not directly by its own key-board, but by the action of the selecting mechanism of the receiving machine, so that there is practically no possibility of the receiving machine printing a wrong letter without the sending machine doing likewise, and thus warning the sending operator of the error.

Each machine is provided with a master switch, by means of which it may be instantly changed from sending to receiving or vice versa. Likewise, each machine is equipped with suitable devices for returning the carriage and rotating the platen at the end of each line,'all of which will be described later in detail.

With these preliminary statements in view, the preferred embodiment of my invention will now bemore fully described with reference to the accompanyingsheets ofdrawings, wherein Fig. l is a plan view, mainly in outline, of my printing telegraph machine, the details of construction heing largely omitted for the sake of clearness. 1

Fig. 2 is'a transverse vertical section, enlarged, taken at the approximate center of the machine.

Fig. 3 is a longitudinal vertical section viewed from the front, showing portions oi the key-operating or printing mechanism.

Figs. 4: and 5 re detailed views of aportion of one key and its operating-mocha nimi, the parts being shown respectively in inoperative and operative positions.

Figs. 6, 7 and 8 are plan views of the selecting mechanism, the parts being shown in two oiilerent operative positions in Figs. 6 and 7 and in normal or inoperative position in Fig. 8.

Fig. 9 is a front elevation of the selecting mechanism, showing also the oscillating motor for operating the same.

Fig. 10 is a part sectional end elevation of the seme,taken approximately on theline l(l10 of Fig. 9 and viewed in the direction of the arrows.

Fig. 111 a plan view of the oscillating motor, taken on the line 11-:11 of Fig. 10.

Fig. 12 is a perspective detail oi? the con tering device for the oscillating motor.

Figs. 13 and 1a are respectively a plan and a erspective of the contact lock.

ig. 15 is a perspective detail of the lock release.

Fig. 16 is a perspective viewof a portion of the selecting mecsm.

Fig. 17 is a perspectiveview of the escapement action of the selecting mechanism. I

Fig. 18 is a perspective view of the escapement release mechani.

Fig. 19 is a perspective view of the selector-return-spring case.

Fig. 20 is a vertical section of the same.

Fig. 21 is a sectional plan of. the'same, taken on the I 21-21 of Fig. 20.

Fig. 22 is a rear perspective detail of the controlling cam for the printing mechanism contact member.

Fig. 23 is a front elevation of the same.

. Fig. 2a is a perspective detail of the lock holding latch.

Fig. 25 is a perspective detail of the prin'te ingFmechanism release trigger.

ig. 26 is an end elevation of the printing mechaninn release latch.

Fig. 27 is a perspective detail of the motor field contact member.

Fig. 28 is a broken sectional plan of the under portion of the typewriter, showing the carriage advancing slide, the hey switches, the contacts for operating the line cut-oh relay, and contacts for operating the platen solenoid.

Figs. 29 and 30 are detailed plan views of the contacts for operating the line outoh rela showing the same in two different position l Fig. 31 is a rear elevation of-the platen, the carriage, and its return mechanism.

Fig. 32 is a detailed plan view of the can ria e advancingmechanism.

igs. 33 and 34: are plan details of the carri return dog, showing the same in two different positions.

Fig. 35 is a diagram of the various electric m'rcuits of one complete machine.

To the drawings, and referring for the present to Figs. 1, 2 and 3 thereof, the not erence numeral 1 desi hates the frame of a typewriter, in which is mounted the usual carriage 2 carrying the platen roller 3. The bars 4 which carry the keys 5, Figs. 1 and 2,

are connected with the type wheel 6 by mechanism which is conventionally illustramd in Fig. 2 and elmignated collectively hy the numeral '4". This mechanism isoi' standard construction, and is well known and connects the hey hars iwith the type wheel 8 such a manner that, when one of said hey hers is depressed, type wheel is first rotated to hring the type character corresponding to the particular operated key in the art,

llO

rec

, to the bottom, and is then swung about its fulcrum 6', descending and striking the platen roller 3, as indicated by the dotted lines, thereby printing the impression of the said type character upon the paper (not shown) which is carried upon said platen. It is understood that the type characters, which are not shown in the drawings, are formed upon the peripheral surface, of the type Wheel 6. The operation of a key bar 4 also causes, through the action of a connecting lever 7 a reciprocating movement of a horizontall disposed slide 8, said slide moving forwardly, or toward the right as viewed in Fig. 2, when the key is depressed, and returning when said key is released. This movement of the slide 8 advances the carriage 2 in a manner to be later described. Springs, one of which is shown at 4' are provided for returning the key bars 4 to their normal positions. I

The connecting mechanism 7' is so arranged that the first portion of the downward movement of a key bar 4 has no efiect on the type Wheel 6. This initial movement of a key bar brings it into contact with a horizontal bar 9, Figs. 2 and 3, carried by a plunger 10 operating through a bushing 11. The lower end of said plunger bears upon a lever 12, Fig. 2, fulcrumed at 13, and whose other end operates the movable contact memoer 14 of a switch 15. Thus when the key is depressed for a portion of its travel, the plunger 10 is forced downward, and the contact 14 is raised to make electrical connection with a stationary contact 16. As shown in Fig. 3, the bar 9 extends under all key bars 4 on the right of the center of the key board, and a similar bar 9' extends under the left hand key bars. Said left hand bar 9 is carried-by a plunger 10 operating in a guide 11, and controls a switch simllar to the switch 15 described above. Said switches are indicated at 15 and 15 in Figs. land 28, and their contacts and electrical connections are shown in Fig. 35 and will be described hereinafter.

It should be clearly understood that the manual operation of any given key 5 does nothing but operate the switch 15, or 15" as the case may be) The electric circuits wh ch are thereby energized cause the operation of mechanism which will be described presently, and which operates to further depress the same key which has been partially depressed by the operator, thereby causlng the printing of the type character corresponding to that key. This action occurs in the sending machine, and at the same time the corresponding key of the receiving machine is also fully depressed, thereby printing the same character in both machines. In actual practice it may be convenient to provide a suitable stop or latch to l mit the initial downward movement of the key of the sending machine to that necessary to operate the switch 15, or 15, said latch being later auto- 1 matically released to allow the further downas herewith il ustrated, depresses the key only' enough to operate the switch, but not enough to operate the printing mechanism, described above. v

The mechanism which causes the above mentioned final and complete depression of the initially and partly depressed key will now be described with relation to the sending machine only, the connection between it and the receiving machine, and the controlling circuits therefor, being subsequently discussed. Referring to Figs. 1, 2 and 3, a horizontally disposed square shaft 17 extends over the entire series of key bars 4, and carries at its right hand end a crank 18 which is connected by a spring cushioned link 19, Figs. 2 and 3, with the core 20 of a-solenoid 21, the latter being hereinafter referred to as the printing solenoid. Thus when said core 20 is drawn down by said solenoid 21,

the shaft 17 is partially rotated. A spring a 22 normally holds said shaft in the position shown.

Slidably mounted on the square shaft 17 is a cam 23, Figs. 1 to 5, which is adapted to be shifted to a position immediately above any one of the key bars 4, so that when said shaft 17 is turned by the printing solenoid 21, said cam 23 depresses the key bar above which it has been placed, as shown in Fig. 5, thereby causing the full operation of the printing mechanism.

The cam 23 is shifted upon the square shaft 17 by means of a trunnion arm 24, Figs. 2 to 5, which is connected with a sliding rod 25, and which travels upon a fixed rod 26, as avguide. Said sliding rod 25 extends beyond the left hand end of the machine, and is secured to a member 27, Figs, 1, 8, 9 and 10, which travels upon a fixed guide 28. Said member 27 extends downwardly, and is secured to a slidable rack bar 29, whose teeth mesh with a gear wheel 30, Figs. 6, 7, 8 and 10. The pitch of the teeth of the gear 30 and rack 29 is equal to the distance between two adjacent key bars 4 of the key board, all of which are equally spaced. The gear 30 is fixed upon a rotatahis shaft 31, Figs.'6, 7, 19, 20 and 21, and upon said shaft, above said gear, is freely mounted a drum like chamber formed of two independent parts, a top 32 and a bottom 32. Radially disposed arms 33 and 33 are secured respectively to the two parts 32 and 32 of said chamber, as shown in Figs. 10, 19

and 21. A spring 34, within said chamber, has one of its'ends secured to each part 32 and 32 and normally holds said parts in such position that the arms 33 and 33 lie on either side of a fixed stop 35. The shaft 31 has fixed to it a radial'arm 36 which extends downwardly between the arms 33 and 33, as shown in Fig. 19, so that when the gear is rotated in either direction, it is opposed by the action of the spring 34, and will be returned by said spring to its normal position as shown in Fig. 8.

The gear 30 is rotated, withan intermittent motion, by an oscillating motor 37, Figs. 9, 10 and 11, comprising a field coil 38 and an armature 39. A cross bar 40 is secured to the shaft of said armature, and operates slides 41 and 41, Figs. 10 and 11, which have lugs 42 and 42', respectively, projecting upwardly through plate 43 which separates the motor 37 from the mechanism above. Said slides are thus reciprocated by the oscillation of the motor armature 39. A pair of spring retained pivoted arms 44, Figs. 10, 11 and 12, acting against a radial lug 45 projecting from the armature 39, normally hold said armature in the position shown.

The lugs 42and 42, projecting through the plate 43, operate against dogs 46 and 46, Figs. 6, 7, 8 and 10, which are pivotally mounted on the respective sliding bars 47 and 47, said dogs being adapted for engagement with the teeth of the gear 30. Thus if the motor armature 39 is oscillated counter-clockwise fromthe position shown in Fig. 11, the dog 46 is caused to engage the gear 30, as in Fig. 7, and turns said gear the distance of one tooth. When the motor armature 39 returns to its normal position, the dog 46 is returned by a spring 48, Fig. 8, secured to the sliding bar 47, but the gear 30 is retained in its advanced position by a pawl 49, Fig. 7. Said pawl is normally held out of engagementwith the gear 30 by a latch 50, as in Fig. 6, but.

said latch is operated to release the pawl 49 by a pin 51 projecting from the sliding bar 47 which engages an arm 52 secured to said pawl, as shown in Fig. 7. The pawl, when thus released, is drawn into engagement with the gear 30 by the spring 53 shown in Fig. 8. Thisescapement mechanism is also illustrated in Figs. 17 and 18.

The parts described above are duplicated on the right hand side of the gear 30, as shown, and are numbered correspondingly, being distinguished from those on the left by the addition of the prime mark to each. Thus a clockwise oscillation of the motor armature 39 from its central position, causes a clockwise rota on of the'gear 30. The direction of oscillation of the motor armature is controlled by the key switches 15 and 15, in a inanner to be later described.

Thus if a .key to the right of the center is depressed, the switch 15 is closed, and the motor armature oscillates counter-clockwise, thus rotating the gear 30 counter-clockwise, and moving the rack 29 and the key-depressing cam 23 to the right; and if a key to the left of the center is depressed, the parts are moved in the opposite direction, carrying said cam 23 to the left.

This movement of the gear 30,. shifting the cam 23 to the right or left as the case may be, continues in a succession of steps, the motor 37 being de-energized and its armature returned to its-central position after each step. The movement of the rack 29 and its associated'member 27, Figs. 8 and 9, also carries with it a rod 54, which extends beneath the key bars 4, and is attached to a slide 55, Figs. 2 and 3, operating on a pair of fixed guide rods 56, and carrying a spring contact point 57 which is adapted to make electrical contact with the key bar 4, which has been initially partially depressed by the operator, when the cam 23 is directly over said key bar. This contact completes certain circuits, to be later described, and causes the printing solenoid 21 to operate, thereby rotating the square shaft 17 and causing the cam 23 to fully depress the said key bar, thus completing the printing'operation. At the same time, the current to the motor 37 is reversed, causing the armature to make one oscillation in the reverse direction. This results in freeing the gear 30, which is then returned by its spring 34 to its normal position, carrying the cam 23 and the contact point 57 back to their central, or normal positions. This freeing of the gear 30 is effected in the following manner.

The radial arm 36, Figs. 6, 7, 8, and 10, which is secured to the gear shaft 31, in its normal position engages a lever 58, which is secured, by means of the rotatable pin 35, to a lower lever 59, as shown most clearly in Fig. 18. Said lower lever 59 operates a transverse slide 60, whose ends are adapted .to be moved into the paths of the pins 51 and 51 of the sliding bars 47 and 47, as shown in Figs. 6, 7, and 16. Thus when the gear 30 is turned counter-clockwise, as in Fig. 7, the levers 5,8 and 59 shift the slide 60 to the right so that its right hand end lies in front of the path of the pin 51' of the sliding bar 47'. During this movement said bar 47 has been stationary, as the motor 37 has been oscillating counter-clockwise, and operating the gear 30 through the sliding lanr 47.

The cross slide 60 is parried in a member 61, Figs. 6, 7, 8 and 16, which is movable. fore and aft, and which carries the pawl retaining; Tatchesj50 and 50. Therefore when the motor 47 is reversed by the contact of the point 57 with the partially shaft 17.

depressed key bar, the sliding bar 47 is moved forward, drawing with it the latch carrying member 61, and causing the latches 50 and 51 to engage both pawls 49 and 49'. Then upon the return movement of the motor armature to its normal. position, which occurs at the completion of the printing operation, said member 61 moves rearwardly again to its normal pos'tion', and lifts said pawls from the gear 30, thereby allowing the latter to be returned to its normal position by its spring 34. A spring 62, Figs. 8 and 10, holds the lever 58 and the slide 60 in their off-center position when said lever is freed by the arm 36.

The mechanism described in the preceding paragraph is inter-connected with the mechanism of the printing solenoid 21 and its shiftable cam 23 in such a manner that the latter cannot operate until released by the initial forward movement of the pawl carrying member 61, which movement is caused by the reversal of the motor 37. F or this purpose the member 61 is secured to a pair of spaced levers 63, Figs. 10 and 16, which are fixed upon an over-lying shaft 64. A cam 65, Figs. 6, 7, 8 and 16, is also fixed upon said shaft, and said cam operates a trigger 66, as shown in Figs. 1, 6, 7, 8 and 25, whose end portion normally acts as a lock for a lever 67, Figs. 1, 2 and 26, secured upon the left hand end of the square Thus when the member 61 is drawn forward, the trigger 66 releases said square shaft 17, allowing it to be rotated by the printing solenoid 21 to cause the previously positioned cam 23 to fully depress the desiredkey and complete the printing operation. A spring 68, Fig. 8, returns the member 61 to its normal position.

The spring contact point 57, which makes contact with the partially depressed key bar, is shifted, to the right or'left from its central position, with the cam 23, as described above.

ln order to prevent said contact point 57 i from interfering with the final and full downward movement of the key bar with which it has made contact, it must be caused to lag slightly behind the cam 23, when moved in either direction, so that it will not bedirectly beneath the key bar, as shown in Fig. 5, but such lag' mustnot be great enough to preventsaid contact point from touching said key bar. For this purpose, the shifting rod has a slotted connection with the member 27, as shown at 69, in Figs. 9, 22 and 23, and is provided with a pin 70 which operates in an inclined slot in a rocking member 71 pivotally connected with the member 27 at said point 69. Said rocking member 71 isengaged by a fixed cam 72, Figs. 9, 10, 22 and 23. in such a manner that when the member 27 moves to the right, the rocking member 54 of the contact point 57.

will be depressed at its left hand end, as shown in Fig. 23, thereby forcing the pin 70 to the upper and left hand end of its slot, and shifting the rod 54 slightly to the left with respect to the member 27. This causes the contact point 57 to lag slightly behind the cam 23, which latter is moved directly by the member 27 through the connecting rod 25. VV-hen the member 27 moves to the left, the left hand end of the rocking member 71 will be raised, thereby causing ,the pin 70 to move to the lower and right hand end of its slot, thereby shifting the rod 54 slightly to the right with respect to the member 27, and again causing the contact point 57 to lag slightly behind the cam 23.

The carriage controlling slide 8, Figs. 2 and 28. which is drawn forward by the complete depression of any key, and is returned upon the release thereof, advances the carriage 2 in the usual manner, which may be briefly described as follows, with particular reference to Figs. 28 and 32. A bellcrank lever 73, Fig. 32, is connected at one end with the slide 8, at 74, and its other end is connected with a transversely movable dog 75 provided with teeth 76 adapted to engage the similar teeth of a ratchet 77 secured to the carriage 2, said ratchet being shown in dotted lines. A spring held retaining pawl 78 also engages said ratchet. Thus when-the slide moves forward, or in the direction of the arrow in Fig. 32,'the dog 75 is moved to the left, and when said slide subsequently returns, said dog 75 is moved to the right, carrying the ratchet 7 7 with it and advancing the carriage one step. The pawl 78 retains said carriage in its new position In order to return the carriage 2 at the end of a line, I provide a drum 79, Fig. 31, operated by a spiral spring 80, and having a cord 8l'wo und upon it. the free end of ceding paragraph advances the carriages against the action of said spring 80, and in order to free said advancing mechanism from the ratchet 77, to allow said spring to return the carriage, I provide an additional key 83, Fig. 1, at the center of the key board. This carriage release key 83 moves the slide 8 forwardly further than any of the other keys, through mechanism to be presently-described, thereby causing the finger 73' of the bell-crank 73, Fr 32, to engage the dog 75, lifting its teeth 76 clear of the ratchet 77. Said dog75 also engages the pawl 78 and lifts it clear of said ratchet, so that the carriage is then free to be returned by the spring 80. At the same time, the slide 8 is held in its extreme forward position by a spring actuated latch 84, Figs. 28, 31', 33 and 34. which drops behind the rear end of said slide, as shown in- Fig. 34,

' and remains in such the slide 8 in the usual above, to advance the carriage, although 1t position until raised by a lug 85, Fig. 31, secured to the carria e 2, said lug engaging and raising the late 84 when the carriage is fully returned.

' The forward movement of the slide 8, when actuated by any key except the carriage' release key 83, is so limited that the latch 84 cannot drop behind its rear end.

The forward end of said slide abuts against a shiftable bar 86, Figs. 28 and 29, which,

in turn, engages and moves a swingingcontact arm 87, causing the latters contact point 88 to-connect with a stationary contact 89, as shown in Fig. 29. These contacts 88 and 89 thus limit the normal forward movement of the slide 8. The electrical connection established between them also causes the release of the selecting mechanism, in a manner to be described later. The carriage release key 83, Fig. 2, is mounted on a bar 90, which is fulcrumed at 91 and has a lug 92 adapted to engage the bar 4' of the space key 5'. Said space key, of course, operates manner, as described does not actuate the type wheel 6. The carriage release key bar 90 extends downwardly, and operates a system of levers and links 93 Figs. 2, 3 and 28, which connect with the shiftable bar 86 and cause the latter to move to the left, when said release key 83 is depressed, as shown by the dotted lines in Fig. 28. This causes the end of the slide 8 to abut against said shiftable bar 86 at its cut-away portion 941, as shownin Fig. 30, thereby allowing said slide to move sufliciently far, be-

fore being stopped by the closing of the con-'- tacts 88 and 89, to permit the latch 84 to drop behind its rear end and to free the dog and the pawl 78, Fig. 32, from the carriage ratchet 77.

The movement of the carriage release key bar 90 also'operates a contact arm 95, Figs. 2, 3 and 28, therby closing the contacts 96 and 97, and energizing a circuit which includes a solenoid 98, Figs. 1, 2 and 31. The downward movement of the core 99 of said solenoid 98, as shown in Fig. 2, causes a partial rotation of the platen 3 by means of the link 100 and the ratchet mechanism indicated at 101. Thus the depression of the carriage release key 83 causes both the return of the carriage and the rotative advancement of the platen to a new line.

The mechanical construction and operation of the sending machine have nowbeen fully descri ed. The construction of the receivin that ol the sending machine described above, and its operation 15 similar, except that the keys of the receiving machine are not initially partially depressed. by the operator, the control of its selecting mechanism being derived "from the hey-board of the sending machine. it shall now dscribed the serious electric machine is, of course, identical with rea ers circuits and connections through which both machines are operated, with particular reference to the inter-dependence, mentioned above existing between the selecting mechanism of the two machines, by means of which the possibility or error is reduced to a minimum.

Each machine is provided with a master switch 102, Figs. 11 and 35, by \means or" which it may be adapted for either. sending or receiving. The contacts of said switch are shown in the sending position in Fig. 35. The selectingv mechanism of each machine has associated with it a contact lock comprising a rocking bar 103, Figs. 6, 7, 8

and 9, which is normally held in the osition shown by a spring 1041 Fig. 8. Sai bar is pivotally mounted at 105, and at one end has two spaced contacts 103 and 103*. At its other end said bar has a pin 106, which is adapted to be engaged by a cam 107 carried upon the end of an arm 108. Said arm extends from a transverse lever 109, Figs. 6, 7, 8 and 15 which is pivotally mounted at its center and has forked ends adapted to be engaged by pins 110 and 110' rising respectively from the sliding bars 47 and 417 of the selecting escapement mechanism. Thus when either of the sliding bars t? or 47' moves forwardly, the cam 107, acting against the pin 106, rocks the bar 103, as shown in Figs. 6 and 7.

A movable contact blade 111, Fig. 8, lies between the contacts 103 and 103", and normally connects with the former. Said blade 111 is carried by an arm 112, which is inlcrumed at 113, and whose end portion is positioned to be attracted by an electro-magnet 1142- When said arm 112 is so attracted, the rocking bar 103 ismoved into the position shown in Figs. 6, 7, and 13, and is held in such position by the engagement of a spring actuated latch 115 with a pin 116 secured in said rocking bar. Said latch 115 has two arms by which from the pin 116. One of said arms, 11?, is adapted to be engaged by the cam 10?, as shown in Fig. 13 and the other, 118, is adapted to be engaged by a trip 119, Figs 8, 9 and 21, which is actuated by the path of movement oi the carried by the left hand end printing shaft 17, as shown crank arm 67 out the square in Figs 1, 2

- and 26.

a reversing relay 12 1, Figs. 1 and 35, whose functions will be described presently. The sending and receiving machines are connested lay a single pair of wires, not shown in the rawmgs, which run iirom the nections or binding posts 128 and 125,

it may be released F'.

a lever 120 lying in causing it to connect binding posts of the receiving machine.

further provided with two other pair of binding posts 126 and 126', and 127 and 127 suitable source of current, not shown, 1s connected with each such pair of binding posts of each machine. For convenience in reference, the current supplied through the binding posts 126 and 126 will be termed the primary current, and that supplied through the binding posts 127 and 127/ the secondary current. The primary current of the sending machine is used to excite the line connecting the sending and receiving machines, whereas the secondary current is used locally in each machine. The secondary current of one machine is of opposite polarity to that of theother machine, for a purpose to be hereinafter set forth.

When a key of the sending machine is partially depressed, supposing-such key to be on the right hand side of the key board, the key switch 15 is operated as described above. This permits a current to flow from the primary current source through the following circuit of the sending machine, as shown in Fig. 35, from the binding post 126 through the wire 128 to the kev switch 15, thence through the contacts 14 and 16, which are understood to have been closed by the partial depression of the key, thence through the wire 129 and the contacts 124 and 124 of the reversing relay 124, said contacts being normally closed, thence through the wire 130 and the contacts 102 and 102 of the master switch 102, which is in the sending position as shown, thence through thewire 131 and the contacts 123 and 123 of the line cut-01f relay 123, said contacts being normally closed, thence through the wire 132 to the lock contact blade 111, thence to the lock contact 103, which is normally in contact with said blade 111, thence through the wire 133, the contacts 102 and 102 of the master switch, the wire 134, the lock magnet 114, and the'wires 135 and 136 to the line binding post 125. The lock magnet 114, being thus energized, attracts the arm 112, thereby moving the rocking bar 103, into the position shown in Fig. 13, sald bar 103 being retained in this position by the latch 115. Contact between the blade 111 and the point 103 is maintained as long as current continues to flow through said magnet 114.

From the binding post 125, Fig. 35, the circuit includes the line, not shown, and the receivin machine, the current returning to the sending machine at the binding post 125'. The remainder of the primary circuit then includes the wire 137, the contacts 124 and 124 of the reversing relay 124, the wire 138, the contacts 14 and 16 of the key switch 15, the wire 139, the binding post 126', and thence to the source of current,

not shown. It will be-seen that nothing in the sending machine is directly operated by the completion of the above described circuit except the contact lock 103.

Turning now to the receiving machine, and regarding Fig. 35 as applying thereto, the primary current from the sending machine enters from the line at the binding post 125, and flows through a circuit comprising the wires 136 and 140, the contacts 102 and 102 of the master switch 102, which is understood to be set in a position opposite to that shown, the wire 141, the field coil 38 of the oscillating motor 37, the wire 142,

the contacts 102 and 102 of the master switch 102, the wire 133, the contacts 103 and 111 of the lock, the wire 132, the contacts 123 and 123 of the line cut-ofi' relay 123, thewire 131, the contacts 102 and 102 of the master switch 102, the wire 143, and the binding post 125', from which the line, not shown, runs back to the sending machine. Still referring'to the receiving machine, the energizing of the motor field coil 38 closes the contacts 121 and 122, which completes the secondary circuit as follows from the source of supply, not shown, the secondary current enters at the binding post 127, thence through the wire 144, the motor armature 39, the contacts 122 and 121, the wire 145, the printing solenoid 21, the wire 146,-the binding post 127', and'thence to the source. Thus both the field and the armature of the motor 37 are energized, and the armature makes one movement. On account of the relative directions of the primary, or field current, and the secondary, or armature current, this movement is counterclockwise as viewed in Fig. 11, which moves the sliding bar 47, Fig. 7, forwardly, and rotates the gear 30 and moves the rack 29 one step to the right. This movement of the sliding bar 47 also operates the lever 109 and its associated cam 107, which moves the right hand end of the rocking bar 103 forward, thereby separating the contacts 111 and 103 and breaking the primary circuit, whereupon the motor field 38 is de-energized and the armature 39 returns to its normal position.

This opening of the primary circuit also de-energizes the lock magnet 114 of the sending machine, allowing its armature 112 to return, thereby causing the contact blade 111 to break its connection. with the contact 103 and to make connection with the contact103", the rocking bar 103 being still held by the latch 115. This completes a new local primary circuit in the sending machine comprising the binding post 126, Fig. 35, the wire 128, the key switch contacts 14' and '16, the wire 129, the reversing relay contacts 124 and 124", the wire 130, the master switch contacts 102 and 102", the wire 131, the line cut-off relay contacts 123 and 123", the wire 132, the

lock Contacts 111 and 103 the Wires 14:7 and 142, the motor field coil 38, the wire 141, the master switch contacts 102 and 102, the wires 143 and 137, the reversing relay contacts 12t and 124, the wire 138, the key switch contacts 1 1- and 16 and the wire 139 to the binding post 126. This circuit energizes the motor field coil 38, giving it a polarity opposite to that of the receiving machine in the first mentioned primary circuit, and closing the contacts 121 and 122, thereby completing a secondary circuit in the sending machine similar to the secondary circuit of the receiving machine described above, except that the polarity of the source of-current is reversedfas before stated. This secondary circuit of the sending machine includes its motor armature 39, which on account of the reversed polarity of both field and armature currents, responds in a manner similar to that of the receiving machine, moving the rack 29 one step to the right.

The contact lock 103 of the sending machine, however, is in a different position from that ofthe receiving machine when the latters motor was operated. S'aid lock 103 of the sending machine, as described above, has been held in the position shown in Fig. 13 by the latch 115, so that the pin 106 is not engaged by the cam 107. The movement of said cam, which is caused-by the operation of the motor, therefore causes it to engage the arm 117 of said .latch 115, thereby releasing the bar 103, and

' causing its contact 103 to break connection withthe contact 11 and its contact 103 to again make connection with said contact 11. This opens the local primary circuit of the sending machine, allowing its motor armature to return to its normal position, and re-establishes the original primary circuit including the line and the motor of the receiving machine, which thereupon operates as before to advance its rack 29 a second step.

Thus it will be seen that the selecting mechanism of the receiving machine, actuated by its oscillating motor 37, is operated in a step-by-step movement through thecompletion of the original primary circuit by the initial partial depression of a key on the sending machine, and that each forward step movement of said receiving selecting mechanism causes a similar movement of the sending machine selecting mechanism, through the breaking of the original line circuit and the completion thereby of a local primary circuit in the sending machine, and that the said move ment of the sending selecting mechanism causes another step movement of the receiving selecting mechanism, through the restoring of the original primary line circuit.

neoeero When the selecting mechanism of the sending machine has operated a sufficient number of steps to cause its spring contact point 57, Fig. 3, to make contact with the initially partly depressed key bar 1, the reversing relay 124, Fig. 35, is operated by means of a circuit connected with the primary source of current and comprising the binding post 126, the Wire 128, the key switch contacts 14 and 16, the wire 129, a ground connection on the frame of the machine at 148, the key bar 4:, which, of course, is grounded, the spring contact 57 a wire 1459, a pair of contacts 121 and 122 which are closed by the attraction of the member 121 by the motor field magnet 38, (and which are shown only in Fig. 35), a wire 150, the reversing relay magnet 124:, the wires 151 and138, the key switch contacts 14. and 16 and the wire 139 to the binding post 126'. The energizing of the reversing relay 124 closes a pair of holding contacts 124: and 1243, which shunt the spring contact 57 and the motor field contacts 121 and 122, thereby causing said relay to remain energized until the key switch 15 is opened. The -energizing of said reversing relay also reverses the direction of the primary currents through the line and the motor field coils 3801? both machines, by making connection between contacts 124 and 124*, andbetween oontacts 12 1 and 124C. The other portions of the primary circuits remain as described above.

' When the first reversed primary circuit is established :by the reversing relay 1%, the motor field coil 38 of the receiving machine is given a polarity opposite to that which it had when operating to advance the rack 29 as described above. The polarity of its armature 39, however, remains the same as before. so that said armature moves in an P in i 11. This moves the sliding bar t7, Fig. forwardly, causing its pin 51 to site direction, or clockwise as viewed engage and move the slide 60 and the latch carrying member 61. This actuates the cam 65 and causes the trigger 66. 110 release the square printing cam shaft 17, Fig. 3. Said shaft is then partially rotated by the printing solenoid 21, which is energized at this time by the secondary current. The cam 23, having been positioned over the proper key by the previous movement of the rack 29, thereupon fully depresses said key, completing the printing operation in the receiving machine.

At the end of the downward movement of the selected key bar, the carriage controlling slide 8, Fig. 28, operates to close the contacts 88 and. 89, as previously described. This energizes the line cut-011' relay magnet 123, Fig. 35, of the receivin machine, said relay magnet bemg connecte by a wire 152 with nears the incoming line wire 1 13, and by a wire tially partly depressed by the operator,

' 153 with the contact 88. The other contact returns said key to its normal position, 89 is connected by a wire 154 with the wire thereby breaking the contacts 1s and 16 and 130, from which the current flows as pre- 14 and 16 of the switch 15, which releases 5 viously described to-the other line binding the reversing relay 1% of the wading ma- 7o post 125. The operation of said line cut-0d chine and the line cut-0d relay 123 of the relay 123 closes a pair of holding contacts receiving machine. Both machines are there- 123 and 123, and opens the contacts 123" fore restored to their original normal posiand 123". "Said holding contacts shunt the tions, ready for the partial depression of 10 contacts 188 and 89, and cause said relay to another key of the sending machm'e. If such 75 remain energized until the key-switch key be on the left of the center of the keyof the receiving machine is opened. The board, instead" of on the right, as. described opening of the contacts 123, and 123 breaks above, the key switch 15 isloperated in the primary linecircuit, de-energizing the place of the key switch 15. When the con- 15 motor, and permiting its armature to tacts 14 and 16, and 149' and 16*, Fig. 35, e0 return to its normal position. The return of said switch 15 are closed, the primary cirmovement of the latch carrying member 61, cuits, both the initial line circuit and the Fig. 8, permits thegear 30 and the rack 29 subsequently completed local circuit of the to return, the latter carrying with it the key sending machine, are established as de- 20 depressing cam 23 and the spring contact 57. scribed above except that the direction of the as It isnecessary to provide the line cut-ofi current is reversed. This can be easily seen relay 123 to open the line circuit, for the by reference to Fig. 35 withoutrepeating reason that the above described. reversed the complete description of said circuits. action of the motor armature 39 does not The direction of the current in the secondary move the sliding bar 47, Fig. 8, suficiently circuits remains the same as before. Thereso far forward to enable it to operate the cam fore, the polarity of the field coils 38 of 107, on account of theoperation of the latch both motors being opposite to that described vcarrying member 61. Thelock member 103, in the first instance, said motors perform all therefore, is not moved, as it was'in the first their operations 'inthe opposite direction,

described operation of the motor, and the thereby moving the key depressing cams 23 95- contacts 111 and 103 remain connected. to the left to operate the selected keys.

Moreover, the primaryline circuit must The circuit of t eplatcn solenoid 98 may remain open, to prevent further operation be traced from the secondary binding post of the receiving machine motor, until the 127, Fig. 35, through a wire 155, the platen sending machine has completed its printing solenoid 98, the contacts 96 and 97, and the 10 operation. wires .156 and 146- to the bindingpost 127 All parts of the receivin machine are Said solenoid is therefore only energized thus returned to their norma positions, one when the contacts 93 and 97 are closed by letter having been printed. The breaking the operation of the carriage return key 83, 4 of the primary circuit by the line cutro relay 123 also releases the lock contact .11 of Condensers 157 and 158, Figs. 1' and 35, the sending machine, thereby re-establishing are preferably included in the circuits as the local primary'circuitin said sending ma shown in said Fig. 35, the condenser 157 chine as described above, except that the dibeing connected across the contacts 121 and the action of the reversing relay 124. This the lock contacts 111 and 103 by the-master causes the motor armature of saidjsending switch contacts 102 and 102, when said machine to operate in the reverse direction, master switch is in the sending position as thereby completing the printing operation shown, and across the lock contacts 111 and and returning all parts to their normal posi- 103 by the master switch contacts 102 and 115 tions in a manner exactly similar to that of 102 when in the receiving position. the receiving machine described above. The A brief recapitulation of the o oration lock member 103 of the sending machine, of the machine in printing a sin 0 letter i however, is held by the latch 115 as before, will now be given. It should be u inas shown in Fig. 13, but the cam107 is'not -mind that the actual printing ration in 120 actuated by the reversed action ofthe motor, both machines is accomplished t rough the said latch being released instead by the trip agency of the usual and well known mecha- 119, which is actuated by the square printnism, employed in typewriters of the type ing shaft 17 through the crank 67 and the. described, for connecting-the key bars with 1 arm as previously described. the type wl, whereby said type wheel is restores the lock member 103 to'its original first rota to the rop er point and then position. depressed upon the p aten by the movement The printing operation of fthe send of any given key e electrically conmachine, which involves the automatic f iil l trolled and operated devices, which are in- Fig. 2, as previously described. 1

45 rection of the current has been-reversed by 122. The condenser 158 is connected across 110 0 depression of the key which has been cluded in the present invention, ect'upon the 

